Flumserberg was indeed ace!

Top Tip for my fellow schwarzer shaffen; if you don't already have one, get your lift pass at the shack outside the Unterterzen lift and then walk up the middle aisle to get on the gondolas. Don't queue up the stairs to buy a ticket at the top.

We did this, and when we were walking up the clear stairs, people we'd been on the train with were only halfway up the stairs with the big queues...